Intake pipe

ABSTRACT

An intake manifold for an internal combustion engine in which the intake manifold includes at least one flange for attachment to the engine, at least two intake tube elements, and a manifold chamber communicating with the intake tube elements, the manifold chamber being subdivided by a separator or dividing element into at least two communicating compartments.

BACKGROUND OF THE INVENTION

The invention relates to an air intake manifold for an internalcombustion engine, wherein the intake manifold comprises at least oneflange at the engine end, at least two tube elements, as well as amanifold chamber communicating with the tube elements.

Such intake manifolds are known, for example, in use in passengerautomobiles.

If it is desired to use such intake manifolds in motor vehicles whichmust satisfy strict noise emission requirements, it is a disadvantagethat the tubes produce undesirable noise in various states of operation.

It might be possible to fully enclose an engine compartment or coverareas which produce intense noise with insulating material. This,however, is expensive to manufacture and would therefore increase thecost of the entire vehicle. Furthermore, it would increase weight, whichautomatically would result in an increase in fuel consumption.

SUMMARY OF THE INVENTION

It is thus the object of the invention to improve an air intake manifoldof the kind described above so as to make it lightweight, inexpensiveand quiet.

In accordance with the invention this object is achieved by dividing themanifold chamber of the intake manifold with a dividing element into atleast two communicating compartments.

Due to the presence of the dividing element the formation of vibratorymodes is impeded or suppressed.

An advantageous embodiment of the invention provides for the intakemanifold to be composed of synthetic resin material. The use ofsynthetic resin material makes the intake manifold lighter in weight,thereby lowering fuel consumption.

Furthermore, provision can advantageously be made for the intakemanifold to be manufactured by the half-shell technique. Thismanufacturing technique offers cost advantages with simple shapes.

In another advantageous embodiment of the invention the dividing elementcovers substantially 100% of the manifold chamber cross section. Sincethe dividing element divides the chamber substantially into two parts,the development of modes of vibration is wholly or partially suppressed.

In an advantageous embodiment of the invention, the dividing elementcovers 25 to 75% of the manifold chamber cross section. Even a partialcross-sectional reduction suffices to break up the propagation ofvibration modes, so that this variant results in an additional weightreduction, while the air, as a vibrating mass, interacts through thecross-sectional reduction against a volume of air behind it that acts asa damper. Furthermore, it is important to see to it that the lineardimensions are small in proportion to the wavelength, which preventsscattering in the vicinity of the cross-sectional reduction. It is alsoadvantageous to make the marginal clamping of the dividing elementsresiliently mounted. Advantageously, the dividing element is composedwholly or partially of porous material.

Advantageously, the distance from the dividing element to the manifoldchamber's inner wall is not evenly divisible by the wavelengths whichoccur in the primary operating state or a multiple thereof. Thisprevents the occurrence of standing waves.

In an advantageous embodiment of the invention, the distance from thedividing element to the inner wall of the manifold chamber isadjustable. By appropriate selection of the geometry, or appropriateadaptation of the geometry to the prevailing operating conditions, forexample by means of displaceable intermediate walls moved by means ofelectrical systems or by vacuum-supported elements, the occurrence ofstanding waves is prevented, since they form whenever a wave after, forexample, two reflections comes back to the starting point with the samephasing.

These and other features of preferred embodiments of the invention arefound not only in the claims but also in the description and thedrawings, the individual features can be utilized individually orseverally in the form of sub-combinations in the embodiments of theinvention and in other fields, and may constitute advantageous as wellas independently patentable embodiments for which protection is herebyclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1b show the division of the manifold chamber by a dividingelement.

FIGS. 2a to 2e show embodiments of dividing elements.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The intake manifold 1, which in the embodiment described is made by thehalf-shell technique, has the weld seams 11, typical of this technique,which are seen in FIG. 1a and which join the half-shells 6 and 7together. For the connection to the actual engine block, not shown here,the intake manifold 1 has a flange 2. The tube elements 3 all open intothe manifold chamber 4 which is divided in half by a dividing element 5represented schematically in FIG. 1. The intake manifold 1 is fastenedby means of the mount 9 in the motor compartment of, for example, apassenger automobile. By means of the vacuum connections 10 attached tothe intake manifold 1, the pressure conditions inside the intakemanifold are detected and used, for example, for control purposes. InFIG. 1a can be seen also a connection for exhaust gas recirculation 14on the intake manifold 1.

The intake manifold 1 shown in FIG. 1b has a flange 2 on the engine endby means of which the intake manifold is fastened to the engine block ofan internal combustion engine. This engine flange 2 is connected to amanifold chamber 4 by tube elements 3, which in turn are composed inthis embodiment of synthetic resin half-shell elements 6 and 7. Themanifold chamber communicates in turn with the air filter, which is notshown. The spatial extent of this manifold chamber 4 is limited by adividing element 5 and bounded by a housing wall 8. This dividingelement 5 acts as a barrier against the propagation of vibration modeswhich depend upon the operating state of the internal combustion engine.The intake manifold 1 is secured in the engine compartment by means ofmount 9. The intake manifold 1, which in the embodiment described ismade by the half-shell technique, has, as seen in FIG. 1b, the weldseams 11 typical of this technique. On the intake manifold 1 injectionvalve sockets 12 are provided into which the injection valves, notshown, are inserted, as well as fastening holes 13 by which the intakemanifold is fastened to the engine block.

Alternatively, the entire intake manifold can also be made by the lostwax technique, but for this a certain complexity of geometry isnecessary, such as complicated internal contours, so that if thehalf-shell technique were to be used, several shell molds would benecessary, and consequently the lost wax technique would have advantageswith respect to the cost situation of the manufacturing process.

Different embodiments of dividing elements 5 are shown in FIGS. 2a to2e.

In FIG. 2a the intake manifold illustrated in FIG. 1a is shown insection, whereby the dividing element 5 occupies nearly the entire crosssectional area of the manifold chamber 4. Also shown are the weld seams11 which join the half-shell elements 6 and 7. The intake manifold issecured in the engine compartment by means of the mount 9.

In FIG. 2b the intake manifold 1 illustrated in FIG. 1a is shown insection, whereby the dividing element 5 occupies only about one-quarterof the cross-sectional area of the manifold chamber 4. Also shown arethe weld seams 11 which join the half-shell elements 6 and 7. The intakemanifold is secured in the engine compartment by means of the mount 9.

In FIG. 2c the intake manifold 1 illustrated in FIG. 1a is shown insection, whereby the dividing element 5 occupies only about one-half ofthe cross-sectional area of the manifold chamber 4. Also shown are theweld seams 11 which join the half-shell elements 6 and 7. The intakemanifold is secured in the engine compartment by means of the mount 9.

In FIG. 2d the intake manifold 1 illustrated in FIG. 1a is shown insection, the dividing element 5 occupying about one-third of thecross-sectional area of the manifold chamber 4. Also shown are the weldseams 11 which join the half-shell elements 6 and 7. The intake manifoldis secured in the engine compartment by means of the mount 9.

In FIG. 2e the intake manifold 1 represented in FIG. 1a is shown insection, whereby the dividing element 5 occupies about two-thirds of thecross-sectional area of the manifold chamber 4. Also shown are the weldseams 11 which join the half-shell elements 6 and 7. The intake manifoldis secured in the engine compartment by means of the mount 9.

The dividing elements 5 shown in FIGS. 2b to 2e give a reduction of thenoise emission of the intake manifold, even though the cross section ofthe manifold chamber 4 is reduced to only 25 to 75%. On the one handthis saves additional material, which corresponds to a weight reduction;on the other hand, the air behind the dividing element 5 acts like adamper on the air masses passing through the cross-sectional reductioncaused by the dividing element 5. Another alternative is to be seen inthe resilient mounting of dividing element 5, which leads to a furtherreduction of the noise emission of the intake manifold. Arranging thedividing element 5 in the manifold chamber 4 such that the distancesfrom the housing wall 8 of the manifold chamber is not evenly divisibleby the wavelength of the vibrations produced by the air flow or by aneven multiple thereof, provides for a reduction of the noise emission ofthe intake manifold 1.

An additional alternative, which is not shown in the drawing, providesfor the distance from the dividing element 5 to the housing wall 8 ofthe manifold chamber 4 to be adjustable. By the use either of elementswhich move the dividing wall 5 and are driven by electric motor or thesupport of dividing wall 5 by vacuum-driven elements, it becomespossible to adjust the dividing wall 5 to the ideal position withrespect to the housing wall 8 of the manifold chamber depending on therespective operating state of the internal combustion engine.

What is claimed is:
 1. An intake manifold for an internal combustionengine, said manifold comprising:at least one flange for connection to amotor, at least two tube elements, at least one manifold chambercommunicating with the at least two tube elements, and at least onedividing element which subdivides the manifold chamber into at least twocommunicating partial chambers, wherein said at least one dividingelement comprises, at least partially, a porous material.
 2. An intakemanifold according to claim 1, wherein said intake manifold is formed ofsynthetic resin material.
 3. An intake manifold according to claim 1,wherein said intake manifold is manufactured by the half-shelltechnique.
 4. An intake manifold according to claim 1, wherein saiddividing element occupies substantially 100% of the manifold chambercross section.
 5. An intake manifold according to claim 1, wherein saiddividing element occupies from 25 to 75% of the manifold chamber crosssection.
 6. An intake manifold according to claim 1, wherein thedividing element is spaced from a manifold chamber inner wall a distancewhich is not evenly divisible by a wavelength occurring in a primaryoperating state of the engine or a multiple thereof.
 7. An intakemanifold according to claim 1, wherein said dividing element isadjustable in position to vary the distance from the dividing element toa manifold chamber inner wall.
 8. An intake manifold according to claim7, wherein the position of the dividing element is adjustable independence on the operating state of the internal combustion engine. 9.An intake manifold for an internal combustion engine, said manifoldcomprising:at least one flange for connection to a motor, at least twotube elements, at least one manifold chamber communicating with the atleast two tube elements, and at least one dividing element whichsubdivides the manifold chamber into at least two communicating partialchambers, wherein said dividing element occupies from 25 to 75% of across-section area of the manifold.
 10. The intake manifold according toclaim 9, wherein said intake manifold is formed of synthetic resinmaterial.
 11. The intake manifold according to claim 9, wherein saidintake manifold is manufactured by the half-shell technique.
 12. Theintake manifold according to claim 9, wherein the dividing element isspaced from a manifold chamber inner wall a distance which is not evenlydivisible by a wavelength occurring in a primary operating state of theengine or a multiple thereof.
 13. The intake manifold according to claim9, wherein said dividing element is adjustable in position to vary thedistance from the dividing element to a manifold chamber inner wall. 14.The intake manifold according to claim 9, wherein the position of thedividing element is adjustable in dependence on the operating state ofthe internal combustion engine.
 15. An intake manifold for an internalcombustion engine, said manifold comprising:at least one flange forconnection to a motor, at least two tube elements, at least one manifoldchamber communicating with the at least two tube elements, and at leastone dividing element which subdivides the manifold chamber into at leasttwo communicating partial chambers, wherein said at least one dividingelement comprises, substantially in its entirety, a porous material.